Study: Bariatric Surgery Linked to Significant Decrease in Mortality at 40-year Follow-up

A comprehensive retrospective study with 40 years of follow-up among persons with a history of bariatric surgery found significant reductions in all-cause mortality and cause-specific mortality related to cardiovascular disease (CVD), diabetes, and cancer.

The findings, based on data from nearly 22 000 participants matched in pairs of individuals with severe obesity, with and without a bariatric procedure, included a 16% reduction in risk of all-cause mortality in patients who had bariatric surgery vs those who did not, a 29% reduction in risk of death from CVD, and a 72% reduced risk of death from diabetes-related morbidity.

More sobering findings included an increased risk of death from chronic hepatic disease among surgical vs non-surgical participants and a 2.4 times higher rate of death from suicide that was particularly elevated among younger patients who had bariatric surgery vs matched participants who did not.

Extending promising results

The current study, published online January 25 in the journal Obesity, builds on past retrospective research that has also shown reduced all-cause and cause-specific mortality in post-bariatric surgery patients but that has been limited by design flaws, small cohort size, and short duration of follow-up, according to study authors.

This study group, led by Ted D. Adams, PhD, MPH, of the University of Utah and Intermountain Healthcare, previously reported findings on long-term mortality of Roux-en-Y surgical patients paired with matched nonsurgical patients but the study was limited to a single procedure, included only 7000 participants and follow-up ended in 2002 after beginning in 1984. “The current study extends follow-up up to 40 years and includes almost 22 000 surgical patients representing all four major types of bariatric procedures performed today,” they explain.

The new study

Adams et al tapped data from the Utah Population Database (UPDB), which includes linked, population-based information from Utah with statewide birth and death certificates, driver licenses and ID cards, and voter registration cards. From the UPDB, which maintains links with medical records held by the 2 largest health care providers in Utah, the team identified a cohort of more than 27 000 adults with a history of bariatric surgery between 1982 and 2018.

Individuals who had bariatric surgery (surgery) and those who had not (non-surgery) were matched in 1:1 fashion for age, sex, BMI, and surgery date with a driver license application/renewal date. The study’s primary objective was to determine the association of all-cause mortality and cause-specific mortality risk between surgery and non-surgery patients. Researchers compared mortality rates using Cox regression analysis and stratified rates by patient sex, type of surgery, and age at surgery.

The final cohort included 21 837 matched surgical and nonsurgical pairs, according to the study. Among nonsurgical participants at index date, mean age was 42.3 years, mean BMI was 46.2 kg/m², 87.6% of the cohort was White, and 79.1% were women. Among those in the surgical cohort, mean age was 42.2 years, mean BMI, 46.0 kg/m², the majority (94.4%) of participants were White, and 79.1% were women. Follow-up was to 40 years with a mean of 13.2 years.

FINDINGS

The investigators found that undergoing bariatric surgery vs not having a procedure was associated with a 16% reduction in risk of all-cause mortality (HR, 0.84 [95% CI, 0.70-0.90]; P<.001). Analysis of cause-specific mortality found significant reductions in the surgery vs nonsurgery groups for CVD (29%), cancer (43%), and diabetes-related conditions (72%) (all P <.001).

When data were analyzed by sex, total mortality was also significantly lower for surgery than non-surgery participants for both women(HR 0.86, 95% CI 0.80-0.93; P<.001) and for men (HR, 0.79; 95% CI: 0.69-0.90; P<.001).

Additional analyses of causes of death found that mortality associated with cirrhosis of the liver was significantly higher (83%; P=.02) among surgery vs nonsurgery participants and the risk was highest in the youngest age group, aged 18-34 years. The risk of death from suicide was more than 2-fold higher among those who had bariatric surgery vs those who did not, with the highest risk also seen among those undergoing surgery between the ages of 18 and 34 years.

Promising future

“This important study adds to the mounting evidence that bariatric surgery, not only improves quality of life for patients, but will also increase their life expectancy," said Jihad Kudsi, MD, of the Bariatric Surgery Division of Duly Health and Care, in Illinois. who was not associated with the research, in a statement from The Obesity Society.

"This work will hopefully improve patients’ access to this effective treatment for obesity, which is still limited to only one percent of qualified patients. Also, the study highlights the importance of providing more resources for pre-surgical psychological screening and post-surgery follow up, especially for younger patients.”

Reference: Adams, TD, Meeks H, Fraser A, et al. Long-term all-cause and cause-specific mortality for four bariatric surgery procedures. Obesity. Published online January 25, 2023. doi:10.1002/oby.23646